PTL 1 describes that “while high coding efficiency can be obtained by entropy coding in a conventional data amount control scheme by feedback control, a data amount cannot be made within a certain amount in units of frames or the like, and it is therefore difficult to apply this scheme to a storage-type medium” or the like is taken as a problem and, as a solution to the problem, “to provide a coded output data amount control scheme in which a data amount is controlled so that a coded output data amount in each predetermined segment defined in advance is within predetermined values so that high efficiency coding is performed, the coded output data control scheme including: means which predicts a data amount by taking a segment shorter than the predetermined segment defined in advance as a unit; means which controls a coding process so that a total predicted data amount in the predetermined segment defined in advance is constant based on the predicted data amount obtained by the above-described predicting means; and means which accumulates a difference between the predicted data amount obtained by the above-described predicting means and an actually coded data amount and controls the coding process based on results of the above-described accumulation”.
Also, PTL 2 describes that “to provide an image signal coding control device with small-sized hardware in which code amount assignment is performed with optimum efficiency and a decoded image with less degradation in image quality can be obtained” (refer to [0010] in PTL 2) is taken as a problem and, as a solution to the problem, “an image signal coding control device including a quantization parameter initialization value computing section, a macroblock line quantization parameter computing section, a macroblock activity calculating section, an activity average value calculating section, and a complexity computing section, the device including a classifying section which classifies, based on activities and an activity average value outputted from the activity calculating section and the activity average value calculating section, macroblocks into classes set in advance and outputs class information, and a conversion table section which selects and refers to a conversion table in which table information corresponding to characteristics of the classes are written, according to the class information, and converts a macroblock line quantization parameter outputted from the macroblock line quantization parameter computing section to a quantization parameter for each macroblock” (refer to [0011] in PTL 2).